1. Field of the Invention
The present invention relates to a tracking circuit and a related method thereof, and more particularly, to a pseudo noise code tracking circuit and a pseudo noise code tracking method.
2. Description of the Prior Art
In time domain synchronous orthogonal frequency division multiplexing (TDS OFDM) systems, a receiver needs to perform code acquisition to detect a pseudo noise code (PN code) in a received signal thereof for being synchronized with a transmitter. In prior art, the receiver performs correlation on PN codes in two successive frames of the received signal respectively with a PN code generated by the receiver to thereby generate two sets of correlation values, and then detects the PN code in the received signal according to the peak position of the two sets of correlation values.
However, when the noise induced by the channel does not belong to additive white Gaussian noise, the reliability of the SN code detected only according to the peak position of the correlation values is not high. For example, in the signal frequency network (SFN), the frames to which peak values in two consecutive sets of correlation values correspond may come from different paths, and it will cause the receiver to have a miscarriage of the PN code detection. To raise the detection accuracy of the PN code, the correlation has to be performed with a higher sampling rate, but that will cause burden to the circuit because of a significant increase in computational load.